It is the aim of this paper to identify and analyse directive speech acts in a corpus of Early Modern English and Present-day English written texts from legal, religious and scientific discourse. It starts with a justification of the application of speech act models to the analysis of written texts. Then several descriptive models are compared (Section"2) and the corpus is introduced (Section"3). In Section"4, the research method of the paper is characterised as a combination of form to function and function to form approaches. The results of the analysis are presented in Section"5: in the Early Modern English period all three text categories show similar frequencies of directives, but differ in their realisation strategies. In Present-day English, scientific discourse is much less directive than the other text categories. Diachronic changes are also evident on the plane of realisation strategies; these linguistic changes correlate with functional changes in legal discourse and changes in the discourse community in scientific discourse. The last section summarises the main issues of the paper and offers some modifications for the development of a more powerful descriptive model for directive speech acts.